South Park: The Stick of Truth - Defeat ManBearPig

After you complete Unfriend Al Gore, you will get another message from him saying that ManBearPig is attacking the church. Head over there and you'll see Al Gore dressed up as the creature hiding behind the one tree. You need to do battle with "ManBearPig" in order to finish the quest.

While the battle isn't as difficult as the one with Al Gore, ManBearPig can still provide a little bit of a challenge. One of the first things you want to do is reduce the armor, so any abilities that reduce this will help. It also helps to stack Bleeding up to 5 times, as well as Gross and Burning if you can, as this will reduce his health a good bit on his every turn.

The quest is finished as soon as you defeat ManBearPig and your rewards are the items on his body.